I had a Braun Vario for about 10 years. I threw away the whisk component about 3 years ago because I notice brown fluid running down the stem. I guess a seal had broken and water got into part of the mechanism. I have just thrown away the whole device because I noticed that the rubber ring around the blade has shrunk (from the heat of the dishwasher?) and allowed food to get in and go rotten. I can see from the pictures of the new Braun that the design has changed and I suspect that same problem won't happen again.
It was fantastic for that 10 years though, but I didn't use any of the additional pieces apart from the whisk very occasionally.
It had a steel end and didn't cause any issues with the base of the pans - you just put it in gentle, and like was mentioned, it is no worse than a steel spoon, probably less so.
Now I am looking at Braun vs Bamix for the replacement. I liked the detachable stem of the Braun. Is it a pain to have to take the whole Bamix to the sink to wash it?